Abstract
A 69-year-old man was admitted to our hospital because of progressive numbness in the lower legs and fingertips as well as a burning sensation in the soles of both feet. The patient was diagnosed with anti-myelin-associated glycoprotein (anti-MAG) neuropathy based on increased serum IgM levels and anti-MAG antibody titers. Atypical pulmonary mycobacteriosis was also suspected. Following treatment with tirabrutinib (a second-generation Bruton tyrosine kinase inhibitor), his symptoms improved and the anti-MAG antibody titer and IgM levels decreased. Tirabrutinib may therefore be an effective treatment option for anti-MAG neuropathy, particularly in patients at risk of infection.